In recent years, in radio communication, particularly, in mobile communication, various kinds of data such as images other than speech have become targets of transmission. In accordance with the diversification of transmission targets, it is required to realize a technique of transmitting data at high speed.
OFDM, which is one of the multicarrier transmission schemes, is attracting attention as a transmission scheme capable of responding to the above requirement. In one example of a radio communication system in which an OFDM scheme is applied, a plurality of the same data symbols (hereinafter “repetition symbols”) generated by data symbol duplication (hereinafter “repetition”) from the transmitting side are arranged in the frequency domain (that is, in a plurality of subcarriers) or time domain and transmitted, and these repetition symbols are combined (by maximum ratio combining, for example) on the receiving side (in the following description, the communication scheme associated with such processing is referred to as “repetition OFDM”). In repetition OFDM, a diversity gain can be obtained by combining the repetition symbols, so that it is possible to improve the data reception quality (such as the SNR: Signal to Noise Ratio or SIR: Signal to Interference Ratio, for example) compared to a standard OFDM scheme (in which repetition is not performed).
Another approach for realizing high-speed transmission is the introduction of the interleave technique. It is generally known that the introduction of the interleave technique contributes to reduction in the reception error rate under a fading channel environment. As one example of the technique, an interleave pattern control method for adaptively changing the interleave pattern according to the reception quality of each data position is proposed (for example, refer to Patent Document 1).
Patent Document 1: Japanese Patent Application Laid-open No. 2004-32712